Identify Max CPC
PPC (pay per click) bid management begins with identifying the maximum CPC (cost per click)
you're willing to pay for a given keyword phrase. If you do not know this
value, it is perhaps not advisable to engage in PPC advertising.
The max CPC will change over time and could vary from search engine to search engine.
If you don't know this value, start with an educated guess.
This could be based on an industry rule of thumb or calculated based on internal factors such as profit margins.
For example, let's suppose you're bidding on the keyword phrase "nike shoes" but do
not know your max CPC. One way to estimate a max CPC involves
taking the top 5 bids on Overture and computing the average.
The current bids are: $0.51, $0.50, $0.33, $0.32, $0.31. The average is 39 cents.
Use that as your max CPC to begin with.

A better approach is to base the CPC on your profit margins.
Let's suppose your average sale price on a pair of Nike shoes is $80 and your profit margin
is 20%. That leaves $16 of profit for each shoe. Also, assume that your conversion rate
will be 1% (this is a conservative estimate).
For every 100 visitors from a PPC ad, you expect 1 sale. If you have $16 of ad
spend to spread over 100 visitors, you have 16 cents to spend per click.
Another way to approach this problem is to have an ad spend based on revenue.
For example, if your goal is to spend 15% of revenue on advertising then your ad
spend would work out to $12 per shoe. Again, assuming a conservative 1% conversion rate,
that would leave you with 12 cents per click.
As your campaign progresses and you determine your actual conversion rate,
adjust the CPC accordingly.

Different strategy for Google vs Overture
Adopt different bidding strategies for Google and Overture.
Their PPC systems are quite different and it's worth the effort to identify different bids
across the two search engines for the same keyword phrase.
Overture sponsored results are based solely on bid while Google uses a combination
of bid and CTR (click through rate).
Start with Overture to determine
initial bid range as their bidding system is open.
It's likely that advertisers bidding for keywords
on Overture are also bidding on Google and probably in the same range.
For Google, use the Overture bids as your starting point in the short term
and reduce the bids for the long term if your CTR is high enough.